package com.sf.ams.utils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class AESUtil {
	private static Logger logger = LoggerFactory.getLogger(AESUtil.class);
	 /*
	   * 加密
	   * 1.构造密钥生成器
	   * 2.根据ecnodeRules规则初始化密钥生成器
	   * 3.产生密钥
	   * 4.创建和初始化密码器
	   * 5.内容加密
	   * 6.返回字符串
	   */
	    public static String AESEncode(String encodeRules,String content){
	        try {
	            //1.构造密钥生成器，指定为AES算法,不区分大小写
	            KeyGenerator keygen=KeyGenerator.getInstance("AES");
	            //2.根据ecnodeRules规则初始化密钥生成器
	            //生成一个128位的随机源,根据传入的字节数组
	            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
	            random.setSeed(encodeRules.getBytes());
	            keygen.init(128, random);
	              //3.产生原始对称密钥
	            SecretKey originalKey = keygen.generateKey();
	              //4.获得原始对称密钥的字节数组
	            byte [] raw = originalKey.getEncoded();
	            //5.根据字节数组生成AES密钥
	            SecretKey key = new SecretKeySpec(raw, "AES");
	              //6.根据指定算法AES自成密码器
	            Cipher cipher = Cipher.getInstance("AES");
	              //7.初始化密码器，第一个参数为加密(Encrypt_mode)或者解密解密(Decrypt_mode)操作，第二个参数为使用的KEY
	            cipher.init(Cipher.ENCRYPT_MODE, key);
	            //8.获取加密内容的字节数组(这里要设置为utf-8)不然内容中如果有中文和英文混合中文就会解密为乱码
	            byte [] byteEncode = content.getBytes("utf-8");
	            //9.根据密码器的初始化方式--加密：将数据加密
	            byte [] byteAES = cipher.doFinal(byteEncode);
	          //10.将加密后的数据转换为字符串
	            //这里用Base64Encoder中会找不到包
	            //解决办法：
	            //在项目的Build path中先移除JRE System Library，再添加库JRE System Library，重新编译后就一切正常了。
	            return new String(new Base64().encode(byteAES));
	          //11.将字符串返回
	        } catch (NoSuchAlgorithmException e) {
	        	logger.error("NoSuchAlgorithmException",e);
	        } catch (NoSuchPaddingException e) {
	        	logger.error("NoSuchPaddingException",e);
	        } catch (InvalidKeyException e) {
	        	logger.error("InvalidKeyException",e);
	        } catch (IllegalBlockSizeException e) {
	        	logger.error("IllegalBlockSizeException",e);
	        } catch (BadPaddingException e) {
	        	logger.error("BadPaddingException",e);
	        } catch (UnsupportedEncodingException e) {
	        	logger.error("UnsupportedEncodingException",e);
	        }
	        
	        //如果有错就返加nulll
	        return null;         
	    }
	    /*
	     * 解密
	     * 解密过程：
	     * 1.同加密1-4步
	     * 2.将加密后的字符串反纺成byte[]数组
	     * 3.将加密内容解密
	     */
	    public static String AESDncode(String encodeRules,String content){
	        try {
	            //1.构造密钥生成器，指定为AES算法,不区分大小写
	            KeyGenerator keygen = KeyGenerator.getInstance("AES");
	            //2.根据ecnodeRules规则初始化密钥生成器
	            //生成一个128位的随机源,根据传入的字节数组
	            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
	            random.setSeed(encodeRules.getBytes());
	            keygen.init(128, random);
	              //3.产生原始对称密钥
	            SecretKey originalKey = keygen.generateKey();
	              //4.获得原始对称密钥的字节数组
	            byte [] raw = originalKey.getEncoded();
	            //5.根据字节数组生成AES密钥
	            SecretKey key = new SecretKeySpec(raw, "AES");
	              //6.根据指定算法AES自成密码器
	            Cipher cipher = Cipher.getInstance("AES");
	              //7.初始化密码器，第一个参数为加密(Encrypt_mode)或者解密(Decrypt_mode)操作，第二个参数为使用的KEY
	            cipher.init(Cipher.DECRYPT_MODE, key);
	            //8.将加密并编码后的内容解码成字节数组
	            byte [] byteContent = new Base64().decode(content);
	            /*
	             * 解密
	             */
	            byte [] byteDecode = cipher.doFinal(byteContent);
	            return new String(byteDecode,"utf-8");
	        } catch (NoSuchAlgorithmException e) {
	            logger.error("NoSuchAlgorithmException",e);
	        } catch (NoSuchPaddingException e) {
	        	logger.error("NoSuchPaddingException",e);
	        } catch (InvalidKeyException e) {
	        	logger.error("InvalidKeyException",e);
	        } catch (IOException e) {
	        	logger.error("IOException",e);
	        } catch (IllegalBlockSizeException e) {
	        	logger.error("IllegalBlockSizeException",e);
	        } catch (BadPaddingException e) {
	        	logger.error("BadPaddingException",e);
	        }
	        
	        //如果有错就返加nulll
	        return null;         
	    }
	    
}
